低弗劳德数下挑坎体型对掺气的影响试验

摘要

By varying height and slope, different shape of ramp-type aerator models in variable slope flume are set to discover laws of cavity length and backwater depth over the aerator under different discharge. After analyzing the results of this experiment, the following conclusions are obtained: In the case of other conditions remain unchanged, flow discharge is proportional to the cavity length, and aerator height affects cavity length larger than aerator slope; greater the flow discharge is, lower backwater depth is. And the backwater depth increases with aerator height, indicating that aerator height is not proportional to the reduction of backwater depth; in this experimental condition, when the jet impact angle is 5.5°, the cavity backwater has emerged. Clearly, the emergence of cavity backwater is closely related with the jet impact angle, but in the final analysis it is relevant to flow conditions, the slope of flume, and the shape of aerator.%通过变换坎高及挑坎坡度,制作不同体型的挑坎模型,将其置于可变坡有机玻璃水槽中,研究在不同流量下坎后掺气空腔长度及回水深度的规律.试验结果表明:在其他条件不变的情况下,来流量与空腔长度成正比,挑坎高度对空腔长度的影响比挑坎坡度要大得多；流量越大,空腔回水深度越低,而空腔回水深度却随着挑坎高度的增加而增加,挑坎高度的增加与回水深度的减轻并不成正比；在试验条件下,射流水舌冲击角5.5°时已出现空腔回水,空腔回水的出现与射流水舌冲击角密切相关,但归根结底还是与来流条件、水槽底坡、掺气坎体型的确定有关.